Things change quickly in pop music. Only months ago, quick cutting -- moving rapidly from style to style -- was the thing to do. Agitated and jumpy, the technique mirrored film editing styles at the visual speed with which MTV works. Wednesday night's show at Madison Square Garden, featuring two alternative rock bands, Jane's Addiction and Happy Mondays, wallowed instead in long and undulating pieces that motored along calmly from climax to climax. It was the revenge of the Grateful Dead.

The concert, which was sold out, showed how popular alternative rock has become and how the market has expanded. Only a few years ago, Jane's Addiction was a promising rock band on the college circuit. Often when a band steps up to the arena level, it can't translate. But Jane's Addiction can. It played an exciting set loaded with funk and rock riffs, stretching out and letting its sound rumble and spread out through the auditorium. Basing many of its pieces on bass lines, the band kept all its musical components simple and distinct. Perry Farrell sang shorts bursts of phrases only to give way to a guitar solo, while the bass and drums pounded away at repeating figures.

The band's rhythm section makes it work, with arrangements and rhythms that draw on funk and African music recast in the context of hard rock. Rhythms overflowed and erupted; the guitarist, Dave Navarro, added percussive scratching to the beats while Mr. Farrell yelped short clean phrases. Though the band's influences were obvious -- the Doors and Led Zeppelin, among others -- they weren't offensive; the group managed to turn repetition and a spaced-out flow into something tense and yet relaxed.

The show opened with Happy Mondays, a group from Manchester, England. Relying on 1970's soul and pop as source material, it pulled apart pieces until they seemed like improvised instrumental compositions with occasional bursts of singing. Using one or two chords, the band layered instrument after instrument until the compositions reached dense, swampy textures. Many bands reproduce the flat undynamic flow of recorded music, but Happy Mondays, improvising and fooling around, sounded like a live band -- even though it used tapes to help the sound.